Heat engines usually use piston drives and crankshafts to convert linear motion to rotating motion. There were many attempts to convert gas turbines, which dominate the aviation industry, into a compact vehicle engine. In these attempts, the small turbine rotate at rpm or so, which requires expensive transmission or electric power generation that reduces shaft work efficiency.
Liquid ring machinery are simple, reliable and low noise compressors and vacuum pumps, which convert the shaft work to radial compression without utilizing pistons and crankshafts. Analysis of the different components of shaft work in liquid ring compressors indicate that close to about 50% dissipate at the Liquid Ring-Casing boundary. With the LRRCC, the boundary friction is replaced by frictional bearing, which is less than 10% of the liquid ring dissipation. This makes the LRRCC a competitive partner in the compressor's and the expander's machinery.
Efficient LRRCC compressors/turbines are known from European Patent number 0,804,687, the teachings of which are herein incorporated by reference.